Open Spaces is scored for twelve retuned string instruments and two percussion instruments. As in several of my earlier works (the operas Nacht and Melancholia, String Quartet No. 1, Piano Concerto ‘Fremde Welten’, etc.) the strings of the instruments are detuned microtonally. Microtonal chords can then be produced with the open strings alone, which yields two advantages: on the one hand, a greater certainty of precision in the intonation, and on the other, the fascination of the sound of open strings in a radically more complex harmonic context than would be possible with traditional tuning.

In Open Spaces, six of the string instruments (violins 1-3, one each of the two violas, cellos and basses) are tuned to an overtone chord founded on a low C (C1, the lowest string of the double bass); the tuning of the other six instruments forms a ‘shadow’ of this tuning a sixth of a tone lower. However, these other, slightly lower-pitched instruments, by stopping the string very close to the nut (playing a sixth of a tone higher than the open string), can compensate for the difference and attempt to sound in unison with the other instruments. In this way, the same chord can be played both with the sound of stopped strings as well as with the sound of open strings.

Open Spaces also has connections with the music of the American composer James Tenney, who died in 2006, and whose musical thinking and radical compositions have exercised a strong influence on my work. In Open Spaces I make use of Tenney’s technique of freely "wandering" between the notes of an overtone chord, as well as the slow glissando in a gentle tremolo from his solo violin piece KOAN.